This invention generally relates to intravascular catheters, such as balloon catheters used in percutaneous transluminal coronary angioplasty (PTCA) and stent delivery.
PTCA is a widely used procedure for the treatment of coronary heart disease. In this procedure, a balloon dilatation catheter is advanced into the patient""s coronary artery and the balloon on the catheter is inflated within the stenotic region of the patient""s artery to open up the arterial passageway and thereby increase the blood flow there through. To facilitate the advancement of the dilatation catheter into the patient""s coronary artery, a guiding catheter having a preshaped distal tip is first percutaneously introduced into the cardiovascular system of a patient by the Seldinger technique through the brachial or femoral arteries. The catheter is advanced until the preshaped distal tip of the guiding catheter is disposed within the aorta adjacent the ostium of the desired coronary artery, and the distal tip of the guiding catheter is then maneuvered into the ostium. A balloon dilatation catheter may then be advanced through the guiding catheter into the patient""s coronary artery over a guidewire until the balloon on the catheter is disposed within the stenotic region of the patient""s artery.
The balloon is inflated to open up the arterial passageway and increase the blood flow through the artery. Generally, the inflated diameter of the balloon is approximately the same diameter as the native diameter of the body lumen being dilated so as to complete the dilatation but not over expand the artery wall. After the balloon is finally deflated, blood flow resumes through the dilated artery and the dilatation catheter can be removed therefrom.
In a large number of angioplasty procedures, there may be a restenosis, i.e. reformation of the arterial plaque. To reduce the restenosis rate and to strengthen the dilated area, physicians now frequently implant an intravascular prosthesis called a stent inside the artery at the site of the lesion. Stents may also be used to repair vessels having an intimal flap or dissection or to generally strengthen a weakened section of a vessel. Stents are usually delivered to a desired location within a coronary artery in a contracted condition on a balloon of a catheter which is similar in many respects to a balloon angioplasty catheter, and expanded to a larger diameter by expansion of the balloon. The balloon is deflated to remove the catheter and the stent is left in place within the artery at the site of the dilated lesion.
In both applications, the catheter must be advanced through the body to the heart. Control and advancement of catheters is difficult because of their construction. The body of conventional catheters is long and tubular. The user must frequently manipulate, or torque, the catheter shaft on the proximal end to facilitate advancement of the catheter with a desired orientation on the distal end. To provide the needed control over the movement of the catheter, it is necessary that these tubular catheters be made somewhat rigid. However, catheters must be flexible enough to navigate through the body lumen to arrive at the desired location within the body where the medical procedures will be performed. An overly rigid catheter shaft will not track, or follow, the guidewire. Therefore, reaching the desired location with the rigid catheter is more difficult. In addition, the catheter shaft is lubricious and smooth. A lubricious shaft is necessary to facilitate advancement within the body lumen. A user may have difficulty creating a sufficient grip on the catheter shaft.
Therefore, what has been needed is a device that improves torquability of the catheter without interfering with the tracking and advancing of the catheter. The present invention satisfies these and other needs.
The present invention is directed to a handle member for gripping a catheter shaft to facilitate advancement on a patient""s body lumen. The handle member is configured to be releasably secured to the catheter shaft. Further, the handle is longitudinally displaceable along at least a length of the catheter shaft, so as to be slidably positional along the shaft. The handle member is comprised of a proximal end, a distal end, at least one lumen extending therethrough, and a connecting member.
The proximal end and the distal end of the handle member each have ports. The ports are completely surrounded by the handle member material. The catheter shaft passes through the proximal end port, advances through the lumen and passes through the distal end port. The handle member may be slidably positional on the catheter shaft. In such an embodiment, the connecting member in the handle member can be engaged to connect with the catheter shaft upon reaching a desired position. The connecting member frictionally engages the catheter shaft. The connection allows the handle member to secure to the catheter shaft, so the handle member will not move.
In one embodiment of the invention, the handle member is disposed about a catheter shaft having an adapter attached to the proximal end of the catheter shaft. The handle member is disposed about the catheter shaft at a location distal to the adapter. In yet another embodiment, the handle member is detachably connected to the adapter.
The handle member may have a connecting member of any type that would adequately grip the catheter shaft. Such connecting members include, but are not limited to clips, clamps, clasps, vises, locks and valves. Specifically, a rotational hemostatic valve is an adequate connecting member. A rotational hemostatic valve (xe2x80x9cRHVxe2x80x9d) generally utilizes a three-piece assembly. First, the RHV has a sleeve. The interior of the sleeve had threads. For this invention, the sleeve may be the distal end of the handle member. The RHV also has a cap that extends partially within the sleeve. The cap has threads corresponding to the sleeve internal threads. The third piece is an O-ring, or other compressible member. The cap will compress the compressible member when it is turned within the sleeve. The compressible member then grips the catheter shaft, anchoring the RHV.
An important aspect of this invention is not only the additional control it would grant the user, but the added comfort the user would experience. This is especially true for long procedures. An embodiment of the invention has outer walls, and a taper between the proximal and distal ends and the center of the handle member on the outer wall. This embodiment allows for more comfortable prolonged gripping. Another embodiment includes a deformation of the outer walls in such a way as to enhance user comfort. A specific embodiment defines internal grooves on the outer wall of the handle member. A user may prefer to use such internal grooves as finger holds, allowing the user to have a secure hold on the handle member without an uncomfortable grip. The user is thereby able to work with more control for a long period of time.
Additionally, the handle may be manufactured from a material that is softer than the catheter shaft. Therefore, a wide variety of soft polymeric materials allow for a comfortable grip. Specifically, a thermoplastic rubber such as Santoprene(copyright) thermoplastic rubber from Advanced Elastomer Systems, a soft and sticky material, is a successful material. Alternatively, a polycarbonate may form the push device to provide support and strength, with a layer of Santoprene(copyright) added to provide a better grip.